> there’s an obvious attack on this, but I’ll go ahead and note my position on it: the whole premise that we can do any of this without just using actual matter the ordinary way is so far into magical territory that we might as well ask “what if lephuchans simulated it?” or “what if god imagined the simulation?”—well ok, sure, I guess if magic is involved that could work, but what’s the point of even considering it?

That's one of the main points of using a thought experiment: by declaring axioms explicitly, by fiat ("true" by definition), it prevents the mind from taking advantage of thought terminating get out of jail free cards like this, it forces people to argue their point.